36 WHAT IS DARWINISM? 



in any great degree my theory ; but none of 

 the cases of difficulty, to the best of my judg- 

 ment, annihilate it." (p. 297) When it is re- 

 membered that his theory is, that slight varia- 

 tions occurring in an individual advantageous 

 to it (not to its associates), in the struggle for 

 life, is perpetuated by inheritance, it is no 

 wonder that the case of sterile ants gave him 

 so much trouble. Accidental sterility is not 

 favorable to the individual, and its being made 

 permanent by inheritance, is out of the ques- 

 tion, for the sterile have no. descendants. Yet 

 these sterile females are not degenerations, 

 they are in general larger and more robust 

 than their associates. 



We have thus seen that, according to Mr. 

 Darwin, all the infinite variety of structure in 

 plants and animals is due to the law of natural 

 selection. " On the principle of natural selec- 

 tion with divergence of character," he says, 

 " it does not seem incredible that, from some 

 such low and intermediate form, both animals 

 and plants have been developed, and if we 

 admit this, we must likewise admit that all the 

 organized beings which have ever lived on this 

 earth may be descended from some one pri- 

 mordial form." (p. 573) We have seen also 



